(CBS News) Republican vice presidential candidate Paul Ryan on Wednesday backed nominee Mitt Romney's opposition to extending a wind energy tax credit that is sacrosanct to Iowa voters, a position that could cost the Republican ticket support in this battleground state.

"We think these tax credits are important to get industries up and running, but we don't think they should continue on indefinitely. What we think would be more helpful for all renewable energies is to lower tax rates on businesses," Ryan told Des Moines television station KCCI when asked whether he agreed with Romney that the credit should be allowed to expire at the end of the year.

Though Ryan said he didn't believe the tax credit should be extended "indefinitely," a campaign spokesman clarified that he agreed it should be allowed to expire at the end of the year.

The interviewer followed up by pointing out that a Cedar Rapids company had laid off almost 200 workers because of uncertainty over the credit's future, prompting Ryan to argue for broader changes to the tax code that he said would level the playing field for all businesses.

"We also want to make sure our tax code isn't one that has too many loopholes, which rewards some industries and not the others," Ryan said. "We want to lower tax rates on all the industries. So the way we look at it is, let's set the conditions that make all of these industries more viable and more competitive. ... So we want to lower tax rates across-the-board, not just in one sector but for all sectors of the economy."

Romney's opposition to extending the tax credit has drawn the ire of influential Iowa politicians including U.S. Sen. Chuck Grassley, who likened Romney's position to "a knife in my back" at a town hall meeting in August. Grassley delivered a glowing introduction of Ryan at an event in Adel, Iowa Wednesday morning, portraying him as a Republican able to effectively stand up to President Obama.

Grassley spokeswoman Jill Kozeny said, "Sen. Grassley supports the Romney-Ryan ticket and is communicating with the campaign on many issues, including this one." Grassley sponsored the bill creating the wind energy tax credit in 1992.